The x-ray luminous galaxy cluster population at 0.9 < z < 1.6 as revealed by the XMM-Newton Distant Cluster Project

Abstract

We present the largest sample of spectroscopically confirmed X-ray luminous high-redshift galaxy clusters to date comprising 22 systems in the range 0.90.9 systems do mostly not harbor central dominant galaxies coincident with the X-ray centroid position, but rather exhibit significant BCG offsets from the X-ray center with a median value of about 50 kpc in projection and a smaller median luminosity gap to the second-ranked galaxy of sim0.3mag. We estimate a fraction of cluster-associated NVSS 1.4GHz radio sources of about 30%, preferentially located within 1_s14 from the X-ray center. The galaxy populations in z>sim1.5 cluster environments show first evidence for drastic changes on the high-mass end of galaxies and signs for a gradual disappearance of a well-defined cluster red-sequence as strong star formation activity is observed in an increasing fraction of massive galaxies down to the densest core regions.